Drawer assembly and refrigerator having same

ABSTRACT

Embodiments of the present invention relate generally to a drawer assembly and a refrigerator having the same. More particularly, embodiments of the present invention relate to a drawer assembly and a refrigerator having the same, in which the drawer assembly includes a casing unit configured to slidably move in forward and backward directions in a refrigerating chamber or a freezing chamber and to store food therein, and a space between the casing unit and a shelf disposed at a lower portion of the casing unit is partitioned to additionally store food. In addition to the cashing unit, a support unit is included that is configured to partition a lower space of the casing unit and a coupling unit is included and is coupled to one of: an end of the support unit or a side of the support unit at a position adjacent to the end thereof, the coupling unit configured to be detachably locked to the lower surface of the casing unit.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2018-0049724, filed Apr. 30, 2018, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention relate generally to a drawer assembly and a refrigerator having the same.

Description of the Related Art

A refrigerator is an appliance that allows its contents such as food to be stored in a fresh condition over time through cold air supplied to its internal storage chamber where the cold air is generated by a heat exchange cycle of a refrigerant.

FIG. 1 is a perspective view showing a conventional refrigerator appliance; and FIG. 2 is a reference view showing a casing unit and a shelf provided in the conventional refrigerator.

Referring to FIG. 1, the structure of a general refrigerator 9 includes a main body unit 91 having an internal storage chamber for food storage, and a door unit 93 configured to selectively open and close the front side of the main body unit 91.

Referring to FIG. 2, the main body unit 91 includes: a box shaped casing unit 911 of a drawer type and used to store food therein; and a shelf 913 to hold food and drinks placed on the upper surface thereof.

Particularly, an example will be described where the casing unit 911 is disposed at the upper portion of the storage chamber of the main body unit 91, and the shelf 913 is disposed right below the casing unit 911. When the casing unit 911 and the shelf 913 have a space therebetween that is larger than necessary, this situation is problematic because the space between the two components is not efficiently utilized.

That is, because there is a limit in the height of the contents that can be placed on the shelf 913, much of the space between the casing unit 911 and the shelf 913 may not be available for use.

This unused space has been a problem because it lowers the usability of the refrigerator 9.

Therefore, to solve the above-described problem, the embodiments of the present invention disclose a drawer assembly and a refrigerator having the same, in which usability is increased over the conventional designs.

The foregoing is intended merely to aid in the understanding of the background of the present invention, and is not intended to mean that the present invention falls within the purview of the related art that is already known to those skilled in the art.

SUMMARY OF THE INVENTION

Accordingly, the embodiments of the present invention have been made keeping in mind the above problems occurring in the related art, and it is a first object of the present invention to provide a drawer assembly and a refrigerator having the same, in which a support unit is provided to partition a lower space disposed below a casing unit which is disposed in a storage chamber of a refrigerator, such that contents may be additionally loaded to increase usability of the refrigerator.

Further, it is a second object of the present invention to provide a drawer assembly and a refrigerator having the same, in which a support unit is rolled around an automatic winding unit, such that the support unit (exposed outside by a user) is automatically wound toward the inside of the automatic winding unit after use, thereby increasing its ease of use and user convenience.

Further, it is a third object of the present invention to provide a drawer assembly and a refrigerator having the same, in which an automatic winding unit and/or a support unit is configured to be detachable from a lower surface of a casing unit, thereby increasing user storage selections/preferences while maintaining overall aesthetics of the appliance.

Further, it is a fourth object of the present invention to provide a drawer assembly and a refrigerator having the same, in which the otherwise unused space in the refrigerator can be efficiently used. In particular, when the casing unit 911 and the shelf 913 are positioned such that a space therebetween is larger than necessary, in accordance with embodiments of the present invention, it is now possible to store additional food, etc., without increasing the overall size of the refrigerator.

In order to accomplish the objects of the present invention as described above and to carry out the characteristic functions of the present invention described below, features of the present invention are as follows.

More particularly, embodiments of the present invention relate to a drawer assembly and a refrigerator having the same, in which the drawer assembly includes a casing unit configured to slidably move in forward and backward directions in a refrigerating chamber or a freezing chamber and store food therein. In addition, a space between the casing unit and a shelf disposed at a lower portion of the casing unit is advantageously partitioned allowing additional food storage.

According to an embodiment of the present invention, a drawer assembly includes: a box shaped casing unit with an open upper portion that is configured to store contents therein; a support unit configured to partition a lower space of the casing unit; and a coupling unit coupled to an end of the support unit or coupled to a side thereof and at a position adjacent to the end thereof to be detachably locked to a lower surface of the casing unit.

According to an embodiment of the present invention, the support unit disposed in the drawer assembly may be formed in a mesh structure or made of an elastic material.

According to an embodiment of the present invention, the support unit disposed in the drawer assembly may have multiple layers.

According to an embodiment of the present invention, the drawer assembly further includes an automatic winding unit disposed on the lower surface of the casing unit and configured to allow the support unit (exposed outside) to be automatically wound inwardly, and wherein the support unit is rolling locked to an inside of the automatic winding unit.

According to an embodiment of the present invention, the automatic winding unit disposed in the drawer assembly includes: a rotating member having a cylindrical shape and configured to roll the support unit in multiple steps along an outer circumferential surface thereof and to be rotated to wind or to unwind the support unit; an elastic member disposed adjacent to the rotating member and configured to provide a restoring force in an opposite direction when the rotating member is rotated in one direction due to unwinding of the support unit; and a contact member coupled to a part of the elastic member to thereby lock an end of the elastic member.

According to an embodiment of the present invention, the contact member disposed in the drawer assembly includes an elastic member-insertion portion that is recessed from one side of the contact portion such that an end of the elastic member is inserted and locked, thereby causing the elastic member to twist due to rotation thereof.

According to an embodiment of the present invention, the casing unit provided in the drawer assembly includes a receiving portion disposed on the lower space thereof to be coupled to the coupling unit, and where the coupling unit is shaped like a hook and configured to be inserted in (and locked to) the ring shaped receiving portion.

According to an embodiment of the present invention, the receiving portion disposed in the drawer assembly is provided in plural, e.g., replicated, along a longitudinal direction on the lower surface of the casing unit. In another embodiment, it is configured to be moveable along the lower surface of the casing unit.

According to an embodiment of the present invention, the casing unit disposed in the drawer assembly includes a receiving portion made of elastic material with a U shaped groove disposed on the lower space thereof to be coupled to the coupling unit, and where the coupling unit is formed in a cylindrical shape to be inserted in the groove of the receiving portion.

According to an embodiment of the present invention, the automatic winding unit disposed in the drawer assembly further includes a housing member that encloses the rotating member and the elastic member in an internal recessed space to form an outer appearance thereof, and where the housing member includes a draw-out hole formed in an outer circumferential surface thereof and along a longitudinal direction such that the support unit can be selectively drawn in and out of the housing member.

According to an embodiment of the present invention, the draw-out hole disposed in the drawer assembly is smaller in height than a thickness of the coupling unit to thereby prevent the coupling unit from being inserted into the housing member.

According to an embodiment of the present invention, the automatic winding unit provided in the drawer assembly is detachably locked to the lower surface of the casing unit.

According to an embodiment of the present invention, a refrigerator appliance is described having a drawer assembly that includes: a body unit formed in a quadrangular column shape, and provided with a storage chamber, which is either a refrigerating chamber or a freezing chamber, the storage chamber for storing food in an internal recessed space; and an opening and closing unit coupled to a front side of the body unit to selectively open and close the internal space of the body unit.

According to an embodiment of the present invention, the casing unit disposed in the refrigerator having the drawer assembly is operable to slidably move along an inner side surface of the freezing chamber (or the refrigerating chamber) and disposed at an upper portion of the freezing chamber (or the refrigerating chamber), where the refrigerator further includes a shelf disposed at a lower portion of the casing unit, and where the support unit is operable to partition a space disposed between the casing unit and the shelf.

According to the above-described configuration, embodiments of the present invention have the following advantages.

An embodiment of the present invention is advantageous in that a support unit is provided to partition a lower space below a casing unit disposed in a storage chamber of a refrigerator, such that contents may be additionally stored to thereby increase usability of the refrigerator.

The present invention is further advantageous in that a support unit is rolled around an automatic winding unit, such that the support unit exposed outside by a user is automatically wound toward inside the automatic winding unit after use, thereby increasing user convenience.

The present invention is further advantageous in that an automatic winding unit and/or a support unit is configured to be detachable from a lower surface of the casing unit, thereby allowing its use in accordance with user preference and while maintaining overall aesthetics of the appliance.

The present invention is further advantageous in that the previously unused space in the refrigerator that is disposed between the casing unit 911 and the shelf 913 can now be used to store additional food, etc., without increasing the overall size of the refrigerator.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view showing a conventional refrigerator;

FIG. 2 is a reference view showing a casing unit and a shelf provided in the conventional refrigerator;

FIG. 3 is a partial perspective view showing a refrigerator in which a drawer assembly according to an embodiment of the present invention is provided;

FIG. 4 is an exploded perspective view showing an automatic winding unit, a support unit, and a coupling unit in accordance with embodiments of the present invention;

FIG. 5 is a side sectional view showing the automatic winding unit to which the support unit is coupled in accordance with embodiments of the present invention;

FIG. 6 is a view showing a state of use of the refrigerator in which the drawer assembly according to the embodiment of the present invention is provided;

FIG. 7 is a reference view showing a state where the coupling unit is coupled to a receiving portion in accordance with embodiments of the present invention;

FIG. 8 is a partial perspective view showing a drawer assembly in which a coupling unit according to another embodiment of the present invention is used; and

FIG. 9 is a partial perspective view showing a state where a plurality of receiving portions is used in accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Specific structural or functional descriptions in the embodiments of the present invention disclosed in the specification or application are only for description of the embodiments of the present invention. The descriptions can be embodied in various forms and should not be construed as being limited to the embodiments described in the specification or application. Further, the present invention may be embodied in many different forms without departing from the spirit and significant characteristics of the invention. Therefore, the embodiments of the present invention are disclosed only for illustrative purposes and should not be construed as limiting the present invention.

FIG. 3 is a partial perspective view showing a refrigerator appliance in which a drawer assembly according to an embodiment of the present invention is shown; FIG. 4 is an exploded perspective view showing an automatic winding unit, a support unit, and a coupling unit; FIG. 5 is a side sectional view showing the automatic winding unit to which the support unit is coupled; FIG. 6 is a view showing a state of use of the refrigerator in which the drawer assembly according to the embodiment of the present invention is provided; FIG. 7 is a reference view showing a state where the coupling unit is coupled to a receiving portion; FIG. 8 is a partial perspective view showing a drawer assembly in which a coupling unit according to another embodiment of the present invention is used; and FIG. 9 is a partial perspective view showing a state where a plurality of receiving portions is used.

Reference will now be made in greater detail to a drawer assembly and a refrigerator having the same according to an embodiment of the present invention with reference to the accompanying drawings.

Referring to FIG. 3, a refrigerator appliance 1 having a drawer assembly according to an embodiment of the present invention is shown and includes a body unit 10 forming an outer appearance of the refrigerator and configured such that an inner space thereof is recessed from a front side to a rear side. The body unit is preferably shaped in a quadrangular column shape, and includes a storage chamber (e.g., a refrigerating chamber or a freezing chamber) for storing food therein. The refrigerator also includes an opening and closing unit (e.g., a door or doors similar to FIG. 1) coupled to a front side of the unit body unit 10 to selectively open and close the internal space of the body unit 10. Further, the number of doors may be two or more when the body unit 10 is divided into upper and lower or left and right compartments. It is appreciated that embodiments of the present invention are not limited to any particular number of doors.

Further, inside the storage chamber of the body unit 10, a drawer assembly 50 is provided to partition the storage chamber in multiple steps to store contents, wherein the drawer assembly 50 may include a casing unit 510, an automatic winding unit 530, a support unit 550, and a coupling unit 570.

The casing unit 510 is, for example, in a box shaped configuration that slides forward and backward and stores contents therein. Further, the casing unit 510 is configured such that an upper portion thereof is open, and is disposed at a lower portion of a shelf to be in close contact with the lower surface of the shelf, thereby ensuring airtightness. Alternatively, the casing unit 510 may be disposed adjacent to the uppermost side of the refrigerating chamber (or the freezing chamber), and the upper portion thereof may be open, but the scope of the present invention is not so limited.

Further, the casing unit 510 is provided on the lower surface thereof with a receiving portion 511 to lock the coupling unit 570 to be described later, and the configuration thereof will be described in detail in the description of the coupling unit 570.

Hereinbelow, before describing the drawer assembly 50 including the automatic winding unit 530 and the support unit 550 in detail, the problems associated with a conventional drawer assembly are described in detail again. For example, when a conventional casing unit 911 (FIG. 2) is disposed adjacent to the uppermost side of the refrigerating chamber (or the freezing chamber) and a shelf 913 is disposed at the lower of the casing unit 911, the space between the casing unit 911 and the shelf 913 may not be be efficiently used. More specifically, when the gap between the casing unit 911 and the shelf 913 is larger than necessary, an unused space results that is not useable for storing food or the like (see FIG. 2).

To solve the above problem, the drawer assembly 50 according to an embodiment of the present invention includes the automatic winding unit 530, the support unit 550, the coupling unit 570, and the like, which will be described in detail, hereinafter.

Referring again to FIGS. 3 to 5, the automatic winding unit 530 is disposed on the lower to surface of the casing unit 510, preferably, is detachably locked to the lower surface of the casing unit 510, such that the support unit 550 that is exposed outside the automatic winding unit 530 is automatically wound toward inside the automatic winding unit 530. For example, the automatic winding unit 530 may be locked to the casing unit 510 at a position adjacent to the rear end of the lower surface of the casing unit 510 such that the longitudinal direction of the winding unit extends in the left and right directions, thereby increasing the overall aesthetics of the components. Alternatively, the longitudinal direction of the automatic winding unit may be locked in the forward and backward directions on the lower surface of the casing unit 510 adjacent to the left and right sides of the casing unit 510 to increase its accessibility, but any side can be selected.

Further, the automatic winding unit 530 may be integrally formed with the lower portion of the casing unit 510, or may be detachable thereto. The detachable structure used may be implemented in any of a variety of well known ways in accordance with the embodiments of the present invention.

The automatic winding unit 530 may include a rotating member 531, an elastic member 533, a contact member 535, and a housing member 537.

Referring to FIGS. 4 and 5, the rotating member 531 preferably has a cylindrical shape, and is configured to roll the support unit 550 in multiple steps along an outer circumferential surface thereof and be rotated to wind or to unwind the support unit 550, as needed. Further, the rotating member 531 may have a rotation shaft in an inner insertion hole formed in the longitudinal direction.

The rotating member 531 may be formed with, for example, male threads along the outer circumferential surface to move toward one end of the housing member 537 during rotation thereof to draw out the support unit 550. On the other hand, the rotating member may be moved back to its original position via rotation by winding the support unit 550 by the to housing member 537.

The elastic member 533 is disposed adjacent to the rotating member 531 and is configured to provide a restoring force in an opposite direction when the rotating member 531 is rotated in one direction due to unwinding of the support unit 550. Accordingly, after a user pulls the support unit 550 away from the automatic winding unit 530 and then releases force that pulls the support unit 550, the rotating member 531 automatically rotates in the opposite direction due to the restoring force of the elastic member 533, whereby the support unit 550 is again wound around the outer circumferential surface of the rotating member 531. The elastic member 533 may be, for example, a spring member.

For example, an end of the elastic member 533 may be inserted into an elastic member-insertion portion 535 a that is recessed from the outer surface of the contact member 535.

The contact member 535 is coupled to a part of the elastic member 533 and remains at the original position even when the rotating member 531 is rotated in one direction so that the stored force can be maintained in the elastic member 533.

The housing member 537 has an internal recessed space along the longitudinal direction to protect the rotating member 531 and the elastic member 533. For example, it is preferable that the housing member 537 has a cylindrical shape. Further, a draw-out hole 537 a may be formed in the outer circumferential surface of the housing member 537 such that the support unit 550 is drawn in and out of the housing member.

It is preferable that the draw-out hole 537 a is of a height suitable for preventing the coupling unit 570 from being inserted into the housing member. For example, when the coupling unit 570 is formed in a rod shape, the height of the draw-out hole 537 a should be smaller than the thickness of the rod. Alternatively, when the coupling unit 570 has a hook shape, the height should be smaller than the thickness of the hook.

The support unit 550 is provided from the automatic winding unit 530 to divide the to space between the casing unit 510 and a shelf 70. This is done so that food or the like can advantageously be additionally stored in the refrigeration chamber or the freezing chamber. For example, the support unit 550 may be formed in a mesh structure or may be made of any material that is easy on which to store food, or the like. Of course, any such material can be used.

Thus, for example, on the upper side of the support unit 550, light weight products such as fruits, vegetables or canned beverages, for instance, can be stored. With this structure, additional storage capacity can be advantageously obtained without increasing the overall size of the refrigerator 1. Further, it is advantageous in that the support unit 550 can be used to increase user storage preferences while maintaining overall aesthetics of the appliance and of the food storage.

Further, to improve bearing capacity, the support unit 550 may be formed in multiple layers, for example, in two or more layers.

Referring to FIG. 4, the coupling unit 570 is coupled to the support unit 550 at an end of the support unit 550 or at a position adjacent thereto, and is locked to the lower surface of the casing unit 510.

Referring to FIGS. 6 and 7, for example, the coupling unit 570 may have a hook like shape and may be operable for insertion in (and locked to) the ring shaped receiving portion 511 disposed on lower surface of the casing unit 510.

Alternatively, referring to FIG. 8, the coupling unit 570 may be formed in a cylindrical bar shape along the longitudinal direction of the support unit 550 at the end of the support unit 550 and may be inserted in a U shaped groove of elastic material provided in the receiving portion 511. In general, a snap fit manner may be used, or any of a number of well known coupling techniques can be used.

Further, referring to FIG. 9, the receiving portion 511 may be configured such that a to plurality of receiving portions are formed, or replicated, on the lower surface of the casing unit 510 along the longitudinal direction of the left and right sides so that the compartment space partitioned by the support unit 550 in the storage space can be user selected. Alternatively, at a side where the receiving portion 511 and the lower surface of the casing unit 510 are coupled to each other, a rail movable along the longitudinal direction may be provided which allows the user to selectively partition the storage space with one receiving portion 511. That is, the receiving portion 511 may be configured to be movable along the lower surface of the casing unit 510.

Therefore, tby using the drawer assembly 50 according to the embodiment of the present invention, it is possible to conveniently use the internal space of the refrigerating chamber or freezing chamber according to user preference, and it is also now possible to increase the usability of the previously unused space in the refrigerator without any increase in the total volume of the refrigerator 1. Further, by the automatic winding unit 530, the support unit 550 is automatically wound, thereby facilitating user convenience, and it is also possible to make the automatic winding unit 530 detachable to increase the overall aesthetics of the refrigerator.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. It is thus well known to those skilled in that art that the present invention is not limited to the embodiment disclosed in the detailed description, and the patent right of the present invention should be defined by the scope and spirit of the invention as disclosed in the accompanying claims. Accordingly, it should be understood that the present invention includes various modifications, additions and substitutions without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

What is claimed is:
 1. A drawer assembly comprising: a casing unit substantially boxed shaped and comprising an open upper portion and a lower surface, the casing unit configured to store contents therein; a support unit configured to partition a lower space of the casing unit; and a coupling unit coupled to one of: an end of the support unit; and a side of the support unit at a position adjacent to the end thereof, wherein the coupling unit is configured to be detachably locked to the lower surface of the casing unit.
 2. The drawer assembly of claim 1, wherein the support unit comprises a mesh structure.
 3. The drawer assembly of claim 1, wherein the support unit comprises an elastic material.
 4. The drawer assembly of claim 2, wherein the support unit comprises multiple layers.
 5. The drawer assembly of claim 1 further comprising an automatic winding unit disposed on the lower surface of the casing unit and configured to allow the support unit exposed outside to be automatically wound inwardly, and wherein the support unit is rolling locked to an inside of the automatic winding unit.
 6. The drawer assembly of claim 5, wherein the automatic winding unit comprises: a rotating member having a cylindrical shape and configured to roll the support unit in multiple steps along an outer circumferential surface thereof and further configured to be rotated to selectively wind and unwind the support unit; an elastic member disposed adjacent to the rotating member and configured to provide a restoring force in an opposite direction when the rotating member is rotated in one direction due to unwinding of the support unit; and a contact member coupled to a part of the elastic member to lock an end of the elastic member.
 7. The drawer assembly of claim 6, wherein the contact member comprises an elastic member-insertion portion recessed from one side of the contact member wherein an end of the elastic member is inserted and locked, causing the elastic member to twist due to rotation.
 8. The drawer assembly of claim 1, wherein the casing unit comprises a ring shaped receiving portion disposed on the lower space thereof to be coupled to the coupling unit, and wherein the coupling unit has a hook like shape and is configured to be inserted in and locked to the ring shaped receiving portion.
 9. The drawer assembly of claim 8, wherein the ring shaped receiving portion is replicated along a longitudinal direction on the lower surface of the casing unit.
 10. The drawer assembly of claim 8, wherein the ring shaped receiving portion is configured to be moveable along the lower surface of the casing unit.
 11. The drawer assembly of claim 1, wherein the casing unit comprises a receiving portion comprising elastic material with a U shaped groove provided on the lower space thereof wherein the receiving unit is configured to be coupled to the coupling unit, and wherein the coupling unit has a cylindrical shape and is configured for insertion in the U shaped groove of the receiving portion.
 12. The drawer assembly of claim 6, wherein the automatic winding unit further comprises a housing member configured to enclose the rotating member and the elastic member within an internal recessed space and provide an overall appearance thereof, and wherein the housing member comprises a draw-out hole formed in an outer circumferential surface thereof along a longitudinal direction and wherein the support unit is configured to be to selectively drawn in and out of the housing member.
 13. The drawer assembly of claim 12, wherein the draw-out hole has a height smaller than a thickness of the coupling unit to prevent insertion of the coupling unit into the housing member.
 14. The drawer assembly of claim 5, wherein the automatic winding unit is detachably locked to the lower surface of the casing unit.
 15. A refrigerator comprising: a body unit having a rectangular shape, and comprising a storage chamber for food storage, the storage chamber being disposed in an internal recessed space of the body unit; an opening and closing unit coupled to a front side of the body unit to selectively open and close the internal recessed space of the body unit; and a drawer assembly comprising: a casing unit substantially boxed shaped and comprising an open upper portion and a lower surface, the casing unit configured to store contents therein; a support unit configured to partition a lower space of the casing unit; and a coupling unit coupled to one of: an end of the support unit; and a side of the support unit at a position adjacent to the end thereof, the coupling unit configured to be detachably locked to the lower surface of the casing unit.
 16. The refrigerator of claim 15, wherein the casing unit is operable to slidably move along an inner side surface of the storage chamber at an upper portion of the chamber, wherein the refrigerator further comprises a shelf disposed at a lower portion of the casing unit, to and wherein the support unit partitions a space between the casing unit and the shelf.
 17. The refrigerator of claim 15 wherein the drawer assembly further comprises: an automatic winding unit disposed on the lower surface of the casing unit and configured to allow the support unit exposed outside to be automatically wound inwardly, wherein the support unit is rolling locked to an inside of the automatic winding unit.
 18. The refrigerator of claim 17, wherein the automatic winding unit comprises: a rotating member having a cylindrical shape and configured to roll the support unit in multiple steps along an outer circumferential surface thereof and further configured to be rotated to selectively wind and unwind the support unit; an elastic member disposed adjacent to the rotating member and configured to provide a restoring force in an opposite direction when the rotating member is rotated in one direction due to unwinding of the support unit; and a contact member coupled to a part of the elastic member to lock an end of the elastic member.
 19. The refrigerator of claim 15, wherein the storage chamber is one of: a refrigeration chamber; and a freezer chamber.
 20. The refrigerator of claim 15, wherein the casing unit comprises a ring shaped receiving portion disposed on the lower space thereof to be coupled to the coupling unit, and wherein the coupling unit has a hook like shape and is configured to be inserted in and locked to to the ring shaped receiving portion. 